Device to Create a Hermetic Seal for Large Openings in Equipment

ABSTRACT

The invention refers to a device to create a hermetic seal for large openings in equipment subject to low pressure. According to the invention it is characterised by at least one sealing cover being provided, which is pressed onto the side wall of the equipment by means of bolts, where the bolts are welded to a strip attached to the side wall at the edge of the opening in the equipment. This provides a good, low-cost and hermetic seal.

The invention relates to a device to create a hermetic seal for large openings in equipment subject to low pressure.

In order to seal openings in equipment, round flanges are normally welded into the opening and a suitable cover with seals is applied. To prevent the seal surfaces from warping, they must have a substantial material thickness and also be machined. For pressure vessels in the medium and high pressure range, the material must be very thick in any case in order to lend the equipment the required strength. At low pressures and for equipment used in air engineering systems, the wall thickness is only a few millimetres and thus cannot guarantee that the sealing surfaces are rigid enough and free of warping, particularly for large, mainly rectangular opening cross-sections. Large cross-sections are needed for assembly and access ports, for example, or for built-in components such as agitators and heat exchangers.

The aim of the invention is thus to create a device that guarantees a simple, low-cost and hermetic seal at low pressures.

The invention is thus characterised by at least one sealing cover being provided, which is pressed onto the side wall of the equipment by means of bolts, where the bolts are mounted in a strip attached to the side wall at the edge of the opening in the equipment, where the opening can advantageously have a rectangular shape. When the device according to the invention is used, the low wall thickness required by the engineering design can be retained, while still achieving a hermetic seal. In particular, there is no need for laborious machining of the sealing surface on the vessel side. This results in an economical advantage in the equipment design.

It has proved particularly favourable if the strip is pressed onto the side wall by means of U-shaped profiles. This ensures that it is pressed on evenly.

A favourable further embodiment of the invention is characterised by the sealing cover having a groove for a soft seal. This provides a very good hermetic seal.

If there are several openings with sealing covers, it is particularly advantageous if sealing covers that are close together are clamped to a shared profile.

A favourable embodiment of the invention is characterised by the bolts being pushed or screwed into the strip, where the bolts can either be glued or welded to the strip.

The invention proves particularly advantageous if the sealing cover is part of a heat exchanger stack, where the heat exchanger stack can be aligned precisely with the aid of running rails and adjustable suspension rollers in such a way that the sealing cover is plane-parallel to the side wall.

The invention will now be described in examples and referring to the drawings, where

FIG. 1 shows an embodiment of the invention,

FIG. 2 shows a sectional view along the line marked II-II in FIG. 1,

FIG. 3 shows a sectional view along the line marked III-III in FIG. 1,

FIG. 4 shows a sectional view of a strip according to the invention, and

FIG. 5 shows a further embodiment of the invention.

FIG. 1 shows a sealing cover 1 that is clamped to the side wall 5 by means of U-shaped profiles 2 using bolts 3 that are welded to a strip 4. The strips 4 are welded to the side wall at the edge of the openings 7 and thus reinforce the sealing area of the side wall. Together with the U-shaped profiles 2, this creates an extremely rigid structure for the sealing area.

FIG. 2 shows a sectional view along the line marked II-II in FIG. 1, where two openings 7 are visible here. The strip 4 is welded to the side wall 5 of the equipment. For sealing purposes there is a U-shaped profile 2 that is connected to the strip 4 by bolts 3 and presses both sealing covers 1 onto the side wall 5. A soft seal 6 placed in the circumferential cover groove in the cover levels out any remaining imprecision in the surface and thus provides a hermetic seal at the opening(s) 7. For openings adjacent to one another, clamping can be achieved in a space-saving arrangement by using a shared U-shaped profile 2 which then has side sections of the same height. In contrast, the side sections for clamping directly to the side wall 5 are not the same height (as also shown in FIG. 3 (sectional view along the line marked III-III in FIG. 1).

The strips 4 have the twin function of stiffening and clamping. Advantageously they have a high, or at least a square cross-section. The bolts 3 are placed or screwed into the holes and welded into place from the rear (see FIG. 4). The strips are then welded to the side wall by means of simple fillet welds following any aligning work that may be necessary.

If there are not only openings 7 to be closed off, but also heat exchanger stacks, for example, that are to be pushed into the equipment from the side, additional measures are required. As shown in FIG. 5, it is advantageous if the heat exchangers also have a sealing plate 1 at their outer end, as described above. The inlet and outlet of the pipe coils 8 lead into collection pipes 9 on the outside. The passages through the sealing plate 1 are seal-welded. At their inner end the pipe coils 8 are secured to a holding frame 10. This holding frame 10 can be connected directly to the sealing plate 1 by means of stiffener plates (not shown), which results in a compact unit. If the insertion depths are large, however, the reinforced side wall 5 according to the invention is not able to withstand the bending weights. As a remedial measure, the side walls facing one another are connected by means of running rails 12, which alone provide some reinforcement. Furthermore, the holding frame 10 of the heat exchanger is suspended from the running rails 12 on adjustable rollers 11. When the heat exchanger stack has been pushed into the equipment, the sealing plate 1 can be aligned plane-parallel to the side wall 5 and thus is not exposed to any additional moments of flexion that cause leakage. The sealing plate is secured in place and sealed by means of U-shaped profiles 2 and strips with bolts 4 according to the invention, as described above. 

1. A device to create a hermetic seal at the edges of large openings in side walls of equipment subject to low internal pressure, comprising: at least one sealing cover (1) pressed onto the side wall (5) of the equipment by a U-shaped profile (2) that is connected to a strip (4) by bolts (3), where the bolts (3) are mounted in said strip (4) that is fitted to the side wall (5) of the equipment, along the edge of the opening (7) in the equipment.
 2. The device according to claim 1, wherein the openings (7) have a rectangular shape.
 3. The device according to claim 1, wherein the sealing cover (1) has a groove for a soft seal (6).
 4. The device according to claim 1, wherein two sealing covers (1) over a respective two openings that are close together are clamped to a shared profile (2).
 5. The device according to claim 1, wherein the bolts (3) are pushed or screwed into the strip (4).
 6. The device according to claim 5, wherein the bolts (3) are either glued or welded to the strip (4).
 7. The device according to claim 1, wherein the sealing cover (1) is part of a heat exchanger stack.
 8. The device according to claim 7, wherein the heat exchanger stack is supported by adjustable suspension rollers for aligning precisely with running rails (12) within the equipment in such a way that the sealing cover (1) is plane-parallel to the side wall (5).
 9. A device to create a hermetic seal around the edge of an opening in a side wall of equipment subject to low internal pressure, comprising: a sealing cover that covers the opening and extends beyond the edge of the opening onto a portion of the wall around the opening; at least one rigid strip attached to the wall adjacent to the cover and having a plurality of projecting bolts; and a plurality of inverted U-shaped clamps that cooperate with the bolts to press the cover against said wall portion.
 10. The device of claim 9, wherein the opening has rectangular edges and a strip is attached to the wall adjacent each edge.
 11. The device of claim 9, wherein a groove is provided in the cover where the cover extends beyond the edge of the opening and a soft seal is provided in the groove and loaded by said clamps against the portion of the wall surrounding the opening.
 12. The device of claim 10, wherein a groove is provided in the cover where the cover extends beyond the edge of the opening and a soft seal is provided in the groove and loaded by said clamps against the portion of the wall surrounding the opening.
 13. The device of claim 9, wherein the strips are welded to the wall and the bolts are rigidly connected to the strips.
 14. A device to create a hermetic seal around the edge of an opening in a wall of equipment subject to low internal pressure, comprising: a sealing cover for covering the opening, having a margin sized to extend beyond the edge of the opening and rest on a margin of the wall around the opening; a rigid strip attachable to the wall adjacent to the margin of the cover; an inverted U-shaped clamp sized for one leg bearing on the margin of the cover and another leg bearing on the margin of either another sealing cover or said wall; a plurality of bolts in said strip for engaging the U-shaped clamp; whereby when the device is assembled around said opening and said bolts tensioned, the margin of the cover is pressed against the margin of the wall, thereby sealing the cover over the opening.
 15. The device of claim 14, wherein the strips are welded to the wall and the bolts are rigidly connected to the strips.
 16. The device of claim 14, wherein the wall has two openings, on either side of an intermediate wall portion; one of said sealing covers is provided over a respective opening; one of said strips is rigidly attached to the intermediate wall portion; a margin of each cover extends over a respective margin of the intermediate wall portion; and the inverted U-shaped clamp has one leg bearing on the margin of one cover and another leg bearing on the margin of the other cover.
 17. The device of claim 16, wherein the strips are welded to the wall and the bolts are rigidly connected to the strips.
 18. The device of claim 14, wherein one of said sealing covers is provided over one opening; one of said strips is rigidly attached to the wall adjacent to the margin of the cover, having one side facing the margin of the cover and an opposite side facing away from the margin of the cover; and the inverted U-shaped clamp has one leg bearing on the margin of the cover and another bearing on the wall adjacent said opposite side of the strip.
 19. The device of claim 18, wherein the strip is welded to the wall and the bolts are rigidly connected to the strips. 